Tracking scope?

[Karl Johnston]

I'm interested in getting involved in shooting starscapes and deep space shots. I keep seeing them and always wonder how they're done.

I particularly wonder how people avoid stars trailing. The only thing astro I've ever done are fields (1 exposure) and northern lights.

But I'm desperate to see what's out there :D

I'm jealous of shots like this:
http://photography-on-the.net/forum/showthread.php?t=674851

What're some of the basics of equipment/astrosoftware I need to invest in?
I've read that a tracking scope is what you need to avoid startrails, but where do you get one of those?

[chris.bailey]

To counter the rotation you need a mount that is able to track with quite a high degree of accuracy. Its this accuracy that many of us spend $$$ and lots of time and frustration trying to achieve. In short it is not easy as we are dealing in arcseconds here.

If you have a few lenses up to about 200mm then find a dark site, point it at the sky and take a whole load of 15 to 20 second exposures the aim being to limit the exposure where the effects of rotation are less that the size of a pixel and therefore largely negated in the image. Dont point straight up as that is where rotation is fastest. USe ISO 800 or even 1600 and then stack all the images together using Deep Sky Stacker (a freeware programme that will sum all the images together, reducing noise and allowing the resulting image to be stretched in Photoshop to give the near equivalent of a single image of equivalent exposure). You should with a bit of effort get close to the image you mention. Dark skies helps a lot as you will be capturing more of the photons you want and less of those you dont.

To go further you need a mount capable of following your target through the sky. Now you are getting in to the $$$ and you can spend as many $$$ as you like on a mount. Have a look at the equipment thread to see the crazy lengths some of us go to to make 6 minute or so exposures possible.http://photography-on-the.net/forum/showthread.php?t=578369

[Karl Johnston]

Yikes!!! And i thought the wildlife guys were loaded $$$!

I'll try it out, thanks!

[hollis_f]

Dont point straight up as that is where rotation is fastest.
Being as the OP is in NWT of Canada, straight up will be fairly near the North Celestial Pole, where rotation will be slowest. Or am I talking borrocks again?

[chris.bailey]

Being as the OP is in NWT of Canada, straight up will be fairly near the North Celestial Pole, where rotation will be slowest. Or am I talking borrocks again?

http://www.astrophotoinsight.com/node/7 :-)

[hollis_f]

http://www.astrophotoinsight.com/node/7 :-)

Ah! I get it now. Many thanks.

[chris.bailey]

Ah! I get it now. Many thanks.

I started off imaging with an Alt Az setup so used to wait for objects to get into the right spot before attempting them. Talk about making life difficult :-)

[cruiser]

Hi Karl,

I use a tracking scope to take my wide field shots. It is an HEQ5 mount which I sometimes have a scope attached to. For those wide filed shots I removed the scope and just had the camera attached to the mount as the scope would end up in the field of view of a 10mm lens.
For these long exposures you really need whats called an equitorial mount as it rotates the same way that the stars do. Although it can take some time getting it aligned to begin with. A bit easier for you northen hemisphere folk as you have the north star to help lol.
I will take some shots of the setup soon and post here to give a better idea.

Brett

[cruiser]

Ok, here are 2 shots of the setup I use. One is camera only and the other is with the camera piggybacked onto the scope.
Hope this helps you visualize a way to get it setup.

Of course you can also attach the camera body to the back of the telescope for deep space shots but the tracking needs to be spot on - but better still if guided by other means (more equipment).

Brett